Proper kitchen ventilation is essential for maintaining healthy indoor air quality and preventing structural damage caused by excess moisture. Cooking produces steam, grease particles, and odours that, if left unchecked, can lead to condensation buildup, persistent dampness, and even black mould growth on walls and ceilings. A well-installed cooker hood with effective range hood ducting captures these airborne pollutants at source, venting them safely to the outside before they can spread through your home. This article walks through the practical aspects of selecting, positioning, and installing a ducted cooker hood, from understanding the different types available right through to completing the final electrical connections.
Choosing the Right Type of Cooker Hood for Your Kitchen
Cooker hoods generally fall into two categories: recirculating and extractor (ducted) systems. A recirculating hood passes cooking air through charcoal filters and returns it to the kitchen. While easier to install since no external vent hole is needed, recirculating units are less effective at removing moisture and heat. For kitchens where humidity and odour control are priorities, a ducted extractor system is the superior choice.
Ducted hoods draw cooking air through ducting and expel it outside through an external wall or roof vent. This physically removes water vapour, cooking odours, and grease-laden air from the building envelope. When planning your system, it is important to review the open space requirements for ventilation in buildings to ensure your installation meets minimum airflow standards and does not compromise the overall ventilation strategy of your home.
Key factors when choosing a cooker hood include:
- Extraction rate measured in cubic metres per hour (m³/h). A good rule of thumb is that the hood should be capable of exchanging the kitchen air volume ten times per hour.
- Width of the hood should match or exceed the width of your hob to capture rising steam effectively.
- Noise level measured in decibels (dB). Quieter units (under 55 dB) are preferable in open-plan layouts.
- Duct diameter usually 100 mm to 150 mm. Larger diameter ducting moves more air with less resistance.
For the best results, choose a hood rated for your kitchen size and ensure the duct run to the outside is as short and straight as possible.
Planning the Cooker Hood Position and Ductwork Route
Before any drilling or cutting begins, careful planning will save considerable time and prevent costly mistakes. The cooker hood should be positioned centrally above the hob at the height recommended by the manufacturer, typically between 650 mm and 750 mm above a gas hob and 600 mm to 700 mm above an electric hob. This height ensures efficient capture of steam while keeping the hood within comfortable reach for controls.
Planning the ductwork route is equally important. Every bend, elbow, and length of ducting adds resistance that reduces extraction performance. A straight run to the outside wall is ideal. Where bends are unavoidable, use gradual 45-degree elbows rather than sharp 90-degree turns. The duct should also be kept away from cold roof spaces or unheated areas where condensation could form inside the pipe. Understanding the relationship between dehumidification versus ventilation strategies helps clarify that a ducted extractor physically removes moist air rather than just filtering it, making it far more effective for moisture control.
Before cutting any holes, check for hidden hazards in the wall. Use a stud and cable finder to locate electrical wires, pipes, or other services that may run inside the wall cavity. Mark the centre point for the vent hole carefully and double check that the external discharge point will not cause nuisance to neighbours or vent into an enclosed space.
Tools, Materials and Ducting Types You Will Need
Gathering the right tools and materials before starting will make the installation go smoothly. Most cooker hood installations require the following tools: a power drill with masonry bits, a holesaw or core drill bit matching your duct diameter (usually 100 mm or 150 mm), a spirit level, tape measure, pencil, screwdrivers, cable ties, and a vacuum cleaner for dust control. For the electrical work, you will need a voltage tester, wire strippers, and appropriate cable (typically 1 mm or 1.5 mm twin and earth).
The choice of ducting material directly affects performance and noise levels. The table below compares the most common options.
| Ducting Type | Advantages | Disadvantages |
|---|---|---|
| PVC / Rigid plastic ducting | Smooth interior surface minimises airflow resistance; durable and tear resistant; easy to clean | Requires more space for installation; less flexible around obstacles |
| Semi-rigid aluminium ducting | Can be bent to navigate around obstacles; lightweight | Prone to tearing if over-manipulated; can create an echo effect when the fan is running, increasing noise |
| Flexible foil ducting | Very easy to install in tight spaces; cheapest option | Wrinkled interior surface creates high airflow resistance; easily punctured; not recommended for long runs |
PVC ducting is generally the best option for permanent installations where a straight or gently curved run is possible. Good lighting and ventilation room design principles suggest integrating the duct route into the kitchen layout early, ideally concealing the pipework above wall units or within a service void.
Installing the Cooker Hood Step by Step
With planning complete and materials gathered, the installation can begin. Follow these steps carefully for a safe and professional result.
- Mark out fixing positions. Draw a vertical centre line on the wall above the hob. Mark the hood height and bracket positions using the template supplied with your unit. Check every mark with a spirit level before drilling.
- Cut the external vent hole. Using a core drill bit matching your duct diameter, drill through the external wall from inside to outside. Angle the hole very slightly downward to prevent rainwater from entering. Fit an external vent cover or grille to the outside wall to finish the opening.
- Fit the internal vent plate. Secure the inner wall plate or spigot over the hole. This provides a connection point for the ducting and covers the rough edges of the drilled opening.
- Install wall brackets for the hood. Fix the hanging bracket or mounting plate securely to the wall using rawl plugs and screws suitable for your wall type. Solid masonry walls need different fixings than plasterboard partition walls.
- Run the ducting. Attach one end of the ducting to the hood outlet using cable ties. Run the ducting up to the inner vent plate, keeping it as taut and straight as possible with minimal creases. Secure the other end to the vent plate connection point.
- Fix the hood body to the wall. With the help of a second person, lift the hood onto the mounting bracket. Secure additional fixing screws as specified in the manufacturer instructions.
- Fit the top duct cover. Slide the upper duct section over the lower section. Most systems allow height adjustment through an overlapping design. Secure the top section to its wall brackets, taking care not to scratch stainless steel surfaces.
- Test the fan and light. Before finalising, run the fan on all speed settings and test the light to verify everything operates correctly.
Proper roof ventilation principles apply equally to duct systems that exit through the roof rather than a wall. In either case, the external termination must be fitted with a weatherproof cowl or louvred vent that prevents birds, insects, and rainwater from entering while allowing air to escape freely.
Electrical Safety and Final Connections
Electrical work demands careful attention to safety. The power supply for the cooker hood should be isolated at the consumer unit before any wiring work begins. Run a dedicated 1 mm or 1.5 mm twin and earth cable from a fused connection unit to the hood location. The cable can be hidden by chasing it into the wall, a 20 mm wide channel cut 10 mm to 15 mm deep that is filled and smoothed over after the cable is installed.
Connect the cable to the hood terminals following the manufacturer wiring diagram. The live (brown), neutral (blue), and earth (green and yellow) cores connect to their corresponding terminals inside the hood connection box. Once wired, restore power at the consumer unit and test the hood on all functions before closing up any access panels. A formal commissioning process for ventilation systems includes checking airflow rates at the grille, verifying that duct joints are airtight, and confirming that the external vent flap opens and closes freely. This final verification step is often overlooked but makes a significant difference to long-term performance.
If your duct run passes through a loft or unheated roof space, insulating the ductwork prevents condensation from forming inside the pipe during cold weather. Uninsulated duct runs through cold zones can drip moisture back into the hood, defeating the purpose of the ventilation system. Adding attic ventilation fan strategies in adjacent roof spaces can help manage overall humidity levels and reduce the load on the kitchen extractor.
For households sensitive to noise, consider upgrading to a hood with a remote fan unit mounted externally, leaving only the grille and controls inside the kitchen. This separates the noisiest component from the living space. The same principle applies in bathrooms, where quiet ventilation strategies for bathrooms use remote-mounted fans and acoustic duct lining to minimise disturbance during operation. A well-installed cooker hood not only protects your kitchen from moisture damage and lingering cooking odours but also contributes to a healthier, more comfortable indoor environment for the whole household.